Improvement in chronometer-escapements for watches



ZSheets-Sheetl. F..H. VOIGT.

cHRoNoMETER ESCAPEMENT Fon WATCHES. No.1 80,290. Patented July 25,1876.

.PE'I'ERS, PHOTD-LITHOGRAPHER WASMNGTON, D C.

` ZSheetS-SheetZ. F. H." VOIGT.-

CHRQNOMETER ESCAPEMENT FOR WATCHES. No.180,290 Patented July 25,1875.

FI a. 3.

WITNESSES: JNVENTaR;

. V4/ Mad/@flaw fmw? NA HEFERS, PHOTD-LITHOGRAFHEH, WASNIIIGTDN D C.

UNITED STATES PATENT OTEEIGE.

F. HERRMAN VOIGT, OF BUFFALO, NEW YORK.

IMPROVEMENT IN CHRONOMETER-ESCAPEMENTS FOR WATCHES.

Specification forming part of Letters Patent No. 180,290,`dated July 25,1876 application filed May 18,1876.

To all whom it may concern:

Be it known that I, F. HEREMAN Voler, of Buffalo, in the county of Erieand State of New York, have invented an Improved Chronoineter-Escapementfor Watches, Src.; and I do hereby declare that the followingdescription, taken in connection with the accompanying sheets ofdrawings, forms a full, clear, and

exact specification, wherein are set forth the working of the watch,86o., in which it is used 5 fifth, it shall'not be easily set by suddenand severe shocks; and, sixth, it shall start with the slightestvibration of the balance.

To this end my invention consists in the arrangement, with thebalance-wheel, of a disengaging-spring for the chronometer-lever,constructed in such manner that it will engage with said chronometerwhen traveling with the balance in one direction, and thus to cause thedetent-lever to liberate the escapewheel, and, when traveling in theopposite direction, to avoid said chronometer-lever. It furthermoreconsists in the arrangement of parts and details of construction, aswill hereinatter more fully appear, and be pointed out in the claims.

In order to enable others skilled in the art to which my inventionappertains to make and use the same, I shall proceed to describe itsconstruction and operation, and thereby refer to thehereinbefore-Inentioned drawings, in which- Figure l is a plan of theescapement. Fig.

ing parts in all the figures, which, in regard to size, are greatlyexaggerated.

A is-the balance of a chronolneter or other watch movement. It may beconstructed of any of the most improved designs, with compensation andother arrangements. B is its hub. G is the escape-wheel. D is thedote-ntlever, secured to the staff D, together with thechronometer-lever E, or made in one piece with the same. F is a veryelastic bladespring, securedto the rim of the balance A with one end,and extending to within a short distance of the balance-staff with itsopposite extremity. This extremity of the spring F is provided with adownwardly-projecting hook or pin, F', which engages at certainintervals wthan upwardly-projectin g cam-shaped pivot on the forward endof the chronometer-lever. G is the table, provided with the usual table-]'ewel H.

The spring F is made of any metal having a high degree ofelasticity-gold, platinum, or the alloys thereof, being preferable. Itshould be made very thin, and as light as possible, to allow itsdeflection with the smallest amount of resistance.

The escape-wheel C has teeth double the height usually found on suchwheels, so as to enable the detent-lever to swing above the table G. i

Instead ofthe downwardly-projecting teeth, pins may be inserted into theface of this Wheel to accomplish the object in View.

The operation of my improved chronometerescapement is as follows, towit: Assuming the watch being wound .up and ready for action, the partsof the escapement to which my invention appertains are in the positionillustratedin Fig. 3, Where the slightest movement of the balance inthe. direction of the arrow will cause the chronometer-lever to operatethe detent-lever in such manner as to release that tooth of theescape-wheel which has been resting thereon. the next succeeding toothwill encounter the table-jewel, and, striking it, give sufficientimpulse to the balance to continue its forward' movement until it hasspent its force vin tensioning the hair-spring placed on the balance- Inits forward movement sta'lf. This hair-spring will then cause a reversemovement of the balance, nearly equal to that of the entire forwardmovement, and until the hair-spring has been strained in the oppositedirection sufficiently to cause the balance to again resulne its forwardmovement, where the disengagementof the detent and the striking ofthetable-jewel will be repeated, and the watch thereby continue its motion.

The enga-gement and disengagement of the chronometer-lever E is effectedby the spring F in the following manner: Soon after the balancecommences its forward movement, the projection of the spring F comes incontact with thel cam E of the chronometer-lever E, and causes thislever to turn around its axis until said projection or cam Ef has beenplaced in such position that its forward end coincides with the curvedescribed by the outer edge of the projection F. In this position saidprojection will disengage from the chronometerlever, and leave the sameintact until it has passed the cam, when the said chronometerlever willinstantly resumeits normal position on account of a hair-spring placed011 the' chronometer-lever staff. When the balance returns, theprojection F' will again encounter the cam E', but this cam being convexonv its back, and on account of its position, will cause said spring todeviate from its former course and to pass behind the cam E', leavingthe chronometer-lever intact during its passage over said cam. Afterhaving passed the cam, the spring returns to its normal position toagain engage the samein its forward movement, as hereinbefore described.

It is evident that, as soon as the escapewheel has been liberated by thedetent,'it will continue to revolve until it is again arrested by saiddetent. This lever is actuated by the chronometer-lever and thehair-spring on its staff in such manner that it will immediately returnto its normal position after it has released one tooth of theescape-wheel, and early enough to arrest the next succeedingl tooth. lnthis manner the watch is kept continually moving.

It will be observed that the staff of the chronometer-lever E is placedin close proximity to the table Gr, in fact so close that the tooth ofthe escape-wheel, giving the impulse to the balance, will at once comein contact with the detent. By this arrangement, in combination with thedeviating spring F, I am enabled to reduce the angle of unlocking tosuch an extent that a slight movement only of the two engaging parts isnecessary to disengage, and whereby I obtain very important results7viz: that of absorbing but very little of the circumferential force ormomentum of the balance, and of starting the watch-movement with eventhe very slightest vibration of the balance. This latter result is theall-important one in chronometer-escapements, because it also reducesthe chances of setting to a minimum; in fact, a movement provided withmy improvements7 if run on", will start itself after being wound up, theslight vibrations of the balance while handling the watch heilig morethan sufficient to start the saine, while for the same reason no shocks,however severe, can cause it to set or stop.

In the older and more recent styles of chronometers the balance andchronomcter lever are compelled to travel backward a certain distancebeyond their angle of locking and unlocking in order to pass each otherin the return stroke. This causes additional friction, and particularlyan increase in fact of the angle of locking and unlocking. In movementswhere the two levers performing this locking and unlocking arenon-yielding there is a further serious drawback, viz: that ofdeteriorating the teeth of the escape-wheel or breaking the pivots orjewels in case the movement has run down, and the escapewheel anddetent-lever or similar contrivances have stopped in such position thatsaid detent would ride upon the tooth of the escape-wheel. If, now, thebalance were vibrated, (as will naturally take place, it being the veryrst thing a watch-owner does if he finds his watch not running,) one ofsaid levers would come in contact with the detent-lever; but on accountof that riding upon the tooth of the escape-wheel cannot pass nor movethe same, and thus serious derangements are the natural results. Thisdrawback is entirely overcome in my movement by the arrangement of thespring F and cam E', which causes the said spring to deviate, no matterwhat position the chronometer may be occupying at the time.

[n order to prevent my spring F from defiecting backwardly, I providethe hub of the balance with a steady-pin just behind the projection F',against Which the spring rests during the whole movement of the balance,except while the said projection passes the cam E in its back motion.Instead of such a pin I may insert a pin into the balance-staff, orslide a collar over the same, as a support for said spring. So, also, toprevent the detent from engaging farther than necessary, I provide thechronometer-staff with a suitable staff-stop or similar means to obtainthe desired result. The engaging-surface of this detent is a curvedescribed from the center of the staff, and it does, therefore, not drawin unlocking.

It is obvious that the chronometer-lever E may bcjeweled by inserting aproperly-shaped ruby in its end as a substitute for the cam E', and thatthe detent may be made entirely or partly of aruby, in order to avoidabrasion by friction. So, also, may the projection F of the spring F bemade of a ruby properly attached to said spring; or it, as well as allthe other pivots, pins, Src., may be made of iridium, which, at thepresent state ofthe art, can successfully be shaped into such parts.

The nature of all the elements entering into the construction of myimproved ohronometerescapement is such that they can easily bemultiplied by suitable machinery, that they are not more expensive tomanufacture than any other first-class ohronometer-escapements,

, and that my improved escapement may be substituted for others in oldwatches, 86o.; in fact, it may be made entire by almost any goodwatchmaker, possessing ordinary facilities for repairing watches.

The position of the spring F, in relation to the ohronometer-lever, issuch that when the balance is at rest it will be at right angles to aline drawn through the centers oi' the said balance and theohronometer-lever staff. It may be made to deviate somewhat from thatposition without seriously affecting the proper working; but it will bebest to arrange it as heretofore described.

I am well aware that mechanical devices may be substituted for thespring and cam, such as sliding projections in the hub or staff of thebalance, or a sliding cam and stationary pin, all of which wouldaccomplish the desired result, and are mechanical equivalents of my saidspring and cam.

Having thus fully described my invention, I desire to secure to me byLetters Patent of the United States- 1. The combination, with theohronometerlever E, of the spring F or its equivalent, for operatingsaid ohronometer, substantially as described, for the purpose'stated.

2. The combination, with the balance A, of the spring F and thechronometerlever E, said spring and ohronometer being provided withmeans, substantially as described, for engagement and disengagement, asstated.

3. The combination, with the spring F, having the projection F', ortheir equivalent, of the chronometerlever E, provided with the cam E orits equivalent, said spring being arranged to engage the ohronometer inits forward movement, and to avoid the same in its return stroke,substantially as described, for the use kand purpose mentioned.

In testimony whereof I hereto set my hand in the presence of twosubscribing witnesses.

F. H. VOIGT.

Witnesses:

MICHAEL J. STARK,

FRANK Hmsorr.

